· Not Anymore.
Putting syn into an older car will not hurt it although everyone and their Mom claims it will. Some companies reccomend a cleaner oil and even that is debated if it is really needed. Mobil 1 is the best brand you will get at the Walmart. I run Amsoil which is readily available around here for a bit less than 5 bucks a quart and I have been very happy with the results.